The black beads are produced in the brains of second-level zombies, and the brains of second-level zombies should normally produce citrine, and there is only a very small probability that black beads will be produced.

This black bead has no effect on others, and there are no energy fluctuations in it. In the last days, this thing is worthless, and it is not even as good as a white crystal.

But this black bead is useful to Lin Feng, and the super energy exchange system in the supermarket can be upgraded with black beads. At present, the upgrade progress bar of the super energy exchange system in Lin Feng's supermarket shows one percent, which was the last time Lin Feng used to experiment, and a black bead can bring one percent of the progress to the super energy exchange system.

When he encountered a robbery outside the Beishan base before, Lin Feng collected some black beads. Coupled with the output of today's corpse tide, Lin Feng had a total of one hundred and fifty black beads on hand. This amount is enough to upgrade the Super Exchange System.

Back in the room, Lin Feng entered the supermarket. Before coming to the Super Exchange System, he did not hesitate to put all the black beads into the recovery port in the Super Exchange System.

When the Super Exchange System first appeared, the things inside were already very powerful. Not to mention anything else, Lin Feng's Xuantie bayonet alone was already extremely sharp, and Lin Feng had avoided a lot of dangers with it.

Moreover, the benefits brought to Lin Feng by the bloodline gene in the super exchange system were great, not to mention that his own attributes brought Lin Feng an increase in agility, it was very strange to let the mutant wolf help him before.

And what will happen after the Super Exchange System is upgraded, Lin Feng is looking forward to it.

A burst of silver light flashed, and the progress bar on the super energy exchange system continued to rise, until after the percent report, the silver light flashed. After the silver glow, the progress bar on the Super Exchange System will show 51/1000.

It seems that the next upgrade requires a thousand black beads to complete, and the chance of black beads appearing is small, but he didn't expect that the next upgrade would require so many black beads, which made Lin Feng smile bitterly in his heart.

But now Lin Feng didn't have time to think so much, and hurriedly came to the screen. Lin Feng was ready to see what the upgraded Super Exchange System would look like.

As before, there are still several categories on the Super Exchange System that can be exchanged for different kinds of things. But Lin Feng saw that in addition to the things that he had before. There's something new coming out.

The first is the weapon exchange system, which was originally full of cold weapons, but now there are some more technological weapons.

For example, MRI guns, as well as frequency pulse guns.

The NMR gun is a weapon that is even more advanced than a laser weapon, and it costs 10,000 white crystals in the last days. It is a weapon of great lethality. Even cultivators can be injured.

Although it is powerful, it is absolutely unaffordable for ordinary people. Ten thousand white crystals are not something that everyone can have, and only a few cultivators can barely have so much money. Therefore, it was almost impossible for ordinary people to use the NMR to kill cultivators. The threshold for MRI guns is too high, and it is simply not within the reach of ordinary people.

In the super energy exchange system, this kind of nuclear magnetic gun requires one hundred citrine, although the price is about the same as the market price, but there is still a difference.

Magnetic Magnetic Guns are extremely few in the last days, and few people are able to sell them. Sometimes even if you have money. It may not be possible to buy it. This is like those limited edition weapons in Lin Feng's previous life, the number is extremely small, and it is not something that can be bought casually. Otherwise, Feng Yi, the leader of the Dongshan base before, used one million white crystals to buy a hundred nuclear magnetic guns, which would still be very effective for the strength of the base.

Due to the extremely small number, in the black market of some bases, the price of nuclear magnetic guns has even increased several times. But because the price is too high, few people will spend money on such weapons.

Lin Feng was different, the prices in the super energy exchange system were all fixed. And based on past experience, there is no limit to what can be exchanged.

Other words. Lin Feng could exchange the NMR for a hundred citrine in the Super Base System without any restrictions, and then sell it at a markup. In that case, you can make a lot of money.

But Lin Feng didn't want to do this, although he said that it would make money. But this will put the MRI gun on the market. With such a powerful weapon, it is not necessarily a good thing to circulate it.

However, Lin Feng still exchanged ten nuclear magnetic guns and put them in the apocalyptic table in case of emergency.

Strange to say, things in the supermarket can't be taken out of the apocalyptic table, but things taken out of the Super Exchange System are an exception. Lin Feng had experimented before, and the potions exchanged from the super energy exchange system did not count the number of times. You can take it out as you like.

The Shock Pulse Gun is a strange thing, it doesn't cause any damage to humans and zombies, but it has a lot of power on buildings. Under the power of the Shock Pulse Gun, the walls of the base will be shattered by this weapon.

The Shock Pulse Gun was not something in this world, Lin Feng had never heard of this weapon before. However, there is this thing in the Super Exchange System, which is an exception.

Although Lin Feng really wanted to exchange it for a Shock Pulse Gun, and then use it to destroy all the walls of the Dongshan base. But the price of this weapon is so high that it costs 10,000 citrine. Although he really wanted to get it, Lin Feng could only stop at it.

At present, Lin Feng only has more than 31,500 citrine in his hands, and 30,000 of them were exchanged for diamond rings at the Tianlong Base before. And the other 1,500 citrine were obtained from the corpse tide just now. And after exchanging those ten nuclear magnetic guns, there were only 500 of the 1,500 citrines left.

If it was just to collapse the other party's wall, it was still not worth spending so much citrine.

Lin Feng had just sold a batch of diamonds, and he shouldn't have digested it yet. If he used the diamond to go to the Shenwu Auction House to exchange for citrine at this time, it was a little unlikely.

Lin Feng wanted to spend the money on the blade, this weapon was a bit too extravagant for the current Lin Feng. What he urgently needs most now is to improve his strength, even if he can't reach level 8 cultivators all of a sudden, he must become a leader among level 7 cultivators. Otherwise, Lin Feng would still be in danger against other high-level cultivators. Only by ensuring that you are strong can you survive well in the last days.

And immediately after, Lin Feng discovered that there was a weapon in the weapon interface on the super energy exchange system. When he saw this weapon, Lin Feng immediately felt that his eyes lit up, and this weapon gave him a sense of déjà vu. (To be continued.) )